An experimental investigation was conducted on Haynes Alloy 556 to study the fatigue behavior of the material at elevated temperatures. Fatigue tests were run at constant temperatures ranging from room temperature to 871°C with strain ranges from 0.265 to 1.5 percent resulting in lives between 102 and 106 cycles. Cyclic deformation properties were evaluated based on the fatigue data. Three fatigue life models were evaluated for their ability to predict the isothermal fatigue lives of the material. These included the Ostergren, Frequency Separation and Stress-Strain-Time models. Strengths and weaknesses of each model are discussed based on the experimental results.